Hydraulic transmission



April 9, 1946. A. JENSEN 2,398,313

HYDRAULIC TRANSMI S S ION Filed May 15. 1942 4 3 Sheets-Sheet 1 40 Z3 40"In S 15 Z2 2 Z5 V lNVENTOR Flea-E JE/VE/V )L ATTORNEYS April 9, 1946.A. JENSEN HYDRAULIC TRANSMISSION s Sheets-Sheet 2 Filed May 15, 1942 A TTOKN EY R O T N E V m hee JENfiE/V BY M; M M

April 9, 1946. AQJENSEN HYDRAULIC TRANSMISSION Filed May 15. 1942 ssheets sheet 5 INVENTOR Ewes JE/vsE/v' BY MIA.

MY AM ATTORNEYS.

Patented Apr. 9, 1946 UNITEDv STATES PATENT OFFICE HYDRAULICTRANSMISSION I Aage Jensen, Racine, Wis.

Application May 15, 1942, Serial No. 443,053

14 Claims.

This invention relates to improvements in hydraulic transmissions.

It is, broadly, the primary object of the invention to provide a noveland improved hydraulic transmission which is particularly compactlyorganized and which provides in one compact unit for variation in therelative speed and power of motion transmission and also for thereversal of the direction of operation of the motor.

More specifically, the invention seeks to provide an improved andcompact organization of a pump and motor within a case, with particularreference to a new and improved disposition of the liquid pressure andreturn passages.

Other specific objects of the invention pertain to the improvement ofthe pump and motor devices which comprise a part of the transmissionwith a view to adapting them for use in the apparatus generally and,moreover, with a view to incorporating the reversing feature directlyinto the displacement unit at one end of the device. displacement unitin question will ordinarily function as a motor but is capable of useeither as a pump or motor, as is obvious to one skilled in the art.

Other objects of the invention will be apparent to skilled personsexamining the following disclosures.

Fig. 1 is a view in axial section through a transmission embodying theinvention.

Fig. 2 is a view taken in section taken substantially in the line 2-2 ofFig. 1. v

Fig. 3 is a view in perspective of a part of the rotor shown in Fig. 2.v

Fig. 4 is a view in section taken on line 4-4 of Fig. 1.

Fig. 5 is a view in section taken on line 5--5 of Fig. 1.

Fig. 6 is a fragmentary detail view taken in section on line 6-6 of Fig.5.

Fig. 7 is a view in perspective of the associated stator parts which areillustrated above in Fig. 2 and in Fig. 5.

Fig. 8 is a view in perspective of partially disassembled stator partsshown in Fig. 4, one of such parts comprising the adjustable reversingsleeve.

Like parts are identified by the same reference characters throughoutthe several views.

While the transmission as such will function equally well when power isapplied to either end, the present disclosure assumes that the power istransmitted through the apparatus from its left hand end to its righthand end and with that in mind I have regarded the displacement devicesembled in a transmission case III which may Thecomprise two cup-shapedsections H and I2 clamped together upon intervening partitions l3 bybolts Id. The shaft I5, here assumed, for purposes of illustration, tobe the driven shaft, projects axially from the casing section [2. Theshaft I6, illustratively, assumed to be the driving shaft, enters theside of the casing section I I and carries a worm l1 meshing with a wormgear l8. The use of speed reducing gearing is no part of the invention.

The respective displacement devices which comprise the pump and motorare similar rotary engines of a generally well known type but theydiffer from each other specifically in order to provide reversible ductconnections and variable power output within the compact dimensions ofthe case III as will hereinafter be described.

The body of the rotary engine which, in the present device, constitutesthe pump. is shown in perspective in Fig. 3. It comprises the annularrotor l9, from one end of which projects the reduced diameter bearingsleeve 20. This bearing sleeve is rotatable in a bearing surfaceprovided interiorly by the annular boss 2i on the casing section II. A

The rotor body l9 has slots 23 for radially reciprocable pistons 25(Fig. 1 and Fig. 2). Intersecting each such slot 22 is a chamber 23 forthe rocker arm 26 by means of which the piston is reciprocated. Thepiston is guided at one side by a key 21 and at the other side by aninsert 28 which closes the end of the slot.

To close the piston guideways' about the periphcry of rotor l 9( forconvenience of manufacture) the annulus 30 is pressed onto the rotorbody l9 engaging the closure inserts 28 to hold them in the slots.Annulus 30 provides a bearing for the rotor upon sleeve 3| which iscarried by the partition l3 at the center of the casing.

Pressed onto the rotor I9 from its other end is another annulus 32 whichcarries the worm gear Hi. This arrangement is also for convenience ofmanufacture, since it would be relatively difficult to harden the teethof the worm gear I 8 if these were formed upon a one piece rotor.

Journaled in the rotor body I9 to extend parallel to the axis thereofare the rock shafts 33, the ends of which are squared to takethe rockerarms 28 as shown in Fig. 2. Each of the rocker arms engages in anopening in its associated piston 25 so that the oscillation of the rockshaft 33 will be communicated'to move the piston radially in its slot-22. Each piston is preferably providedwith one or more radial bores 34(Fig. 1) so that as the piston moves radially in its slot it will nottrap liquid above or below the piston but will move freely.

.At their outer ends the respective rock shafts 33. are provided withcam follower levers 35 which appear in cross section in Fig. l and whichbear upon a cam 35 carried by the annular flange 2| of casing sectionII. The form of the rock shafts and the cam follower. levers does notclearly appear in Fig. 1 or Fig. 2 but'a corresponding and substantiallyidentical structure is shown in Figs. and 6 in connection with thedriven member of the transmission which will hereinafter be described.Compression spring 38 hold the levers 35 to the cam 35 and areresponsible for moving thelevers, the rock shafts and the pistons in onedirection, the cam moving these parts in the opposite direction againstthe bias of their respective springs 38.

The inner periphery of the rotor body if! constitutes one cylinder wall.The opposing cylinder wall is provided by the outer periphery of atubular member 40 which is threaded at its left hand end (Fig, 1) to thescrew 41 which projects from the casing section II and is provided witha hand wheel 42 for its rotation. By means of the hand wheel and screwthe tube 40 may be moved axially of the casing but it is nonrotatable.As shown above in Fi 1 and Fig. 7, the tube 40 carries on its outerperiphery the non-rotatable abutments 43 and 44 which constitute thecylinder heads. At one side of each of these cylinder heads is a slot 45(Fig. 7) opening radially through the tube 40 from the interior thereof,the interior passage 46 through the tube 40 constituting a low pressureconduit for liquid supplied to the pumping engine.

The location of the cylinder head abutments 43 and 44 on the peripheryof tube 40 corresponds to the peripheral location at which the cam 38elevates the pistons 25. .As is usual in such devices, the form of thecam causes the pistons to move radially outwardly in their slot to clearthe stationary abutments or cylinder head 43 and 44 after which, in therotation of the rotor, the pistons are returned into engagement with theperiphery of the tube 40.

A displacement sleeve 41 (Fig. 1 and Fig. 7) is constrained by thethrust bearing assembl 48 and the retaining nut 49 (Fig. 1) to moveaxially with the tube 40 subject to the control of screw 4| and handwheel 42. The displacement sleeve 41 is required, however, to rotatewith the rotor body 19 by reason of the fact that it has slots at 50 inwhich the keys 21, previously identified, are engaged.

Fixed within the annular bearing flange 3| of partition I3 is astationary sleeve 55, best shown in Figs. 1, 7 and 8. This sleeve isprovided at 58 with axially extending slots providing high pressurepassages opening from the pumping engine just described to carry liquidfrom the pumping engine through the partition 13 to the motorhereinafter to be described. The slots 55 not only carry high pressureliquid but serve to receive the cylinder head abutments 43 and 44 whenthese are displaced axially by movement. of the tube 40 upon which theyare mounted. Engagement of these abutments with the side of the slots 55holds the tube 44 against rotation. The operation of the'pumping enginemay now be summarized.

Liquid is received from the interior passages 45 of tube 40 through theports 45 into the annular cylinder space between th outer periphery ofthe tubes 40 and the inner periphery of the rotor bodies l9. Fig. 2shows the pistons which are there illustrated at the top and bottom ofthe view, elevated to clear the stationarycylinder head abutments 43 and44 while the pistons which are horizontally illustrated in Fig. 2 arewiping the surface of the non-rotatable tube 40. Ahead of each of theseacting pistons 25 liquid'is being displaced and discharged into the highpressure passage afforded by the slot 55 of the stationary sleeve 55.Behind each of the acting pistons 25 a fresh supply of liquid is beingdrawn into the annular cylinder space.

When the tube 40 is moved axially by the screw 4| and hand wheel 42, thecylinder head abutments 43 travel into the high pressure dischargepassage slots 55 of the stationary sleeve 55 and the annular cylinderspace between the inner periphery of the rotor l8 and the outerperiphery of the tube 40 is thereupon filled to a greater or lesserdegree by the sleeve. The keys 21 maintain the slots 50 of sleeve 41 inregistry with the rotor slots 22 in which the pistons 25 reciprocate, sothat each piston will continue its cam controlled reciprocation into theslots 50 of the displacement sleeve 41. Thus the operation of the partswill continue unimpeded but the effect of the pistons in displacingliquids about the annular cylinder space will be reduced by thedisplacement capacity of sleeve 41 which has invaded such space.

Pumping engines ofthis type being known as to their generalcharacteristics, it is believed that no further description of operationis necessary. Accordingly, the motor will now be described, withparticular reference to high and low pressure communication with thepumping engine through the reversing mechanism.

The cylinder space of the motor engine is of somewhat greater diameterthan that of the pumping engine in order to accommodate the reversingmechanism and the communicating passage. Otherwise the construction isquite similar. There is a rotor body having radial slots at 220 in whichthe pistons 250 are radially reciprocable under the control of rockerarms 250 on rock shafts 330 which are Journaled in the rotor body I30and provided at their outer ends with levers 350 bearing on the cam 350and held thereto by compression springs 380 which seat against the ring800 which is pressed onto the outside of the rotor body to close theends of the slots in which the pistons reciprocate. The driven shaft I5has a flange 58 which is bolted to the body.

Journaled on the outside of the stationary sleeve 55 is an oscillatoryreverse control sleeve 50 (Figs. 1, 4 and 8). This sleeve carries thecylinder head abutments 430 and 440 of the motor engine and it alsocarries the cam 38!! and is provided with a lever 52 projecting from thecasing Ill and constituting a means for oscillat ing the control sleeve50 upon the stationary sleeve 55.

Whereas the pumping engine has but a single slot adjacent each of theabutments 43 and 44, the motor engine has two such slots at 453 and 45lrespectively, one being located at each side of each of the abutments.The underlying fixed aseasrs sleeve 55 has slots at 83 and 64 which aremore widely spaced than slots 450 and I in a peripheral direction, thisbest being illustrated in Fig. 4 where the spacing between the slots isimmediately apparent. The slots 53 and 84 of the stationary sleeve opento the interior oi the sleeve and hence communicate with the returnpassage 46 which extends axially through the tube 40 from the open endof such tube.

With the parts in the position illustrated in the drawings, withparticular reference to Figs. 4 and 5, itwill be apparentthat the highpressure liquid supplied through slots 56 of the stationary sleeve 55will pass radially outwardly at one side of the stationary abutments 430and II through the slots I in the oscillatable reversing sleeve 60 intothe annular cylinder space of the motor engine between the outerperiphery of the reversing sleeve 60 and the inner periphery of therotatable body I80. In such space the high pressure liquid will act onthe piston vanes 250 which are in contact with sleeve 60 to propel thevanes and the rotor in the direction indicated in Fig. 4 by the arrow.The low pressure liquid ahead or each piston vane will leave the annularcylinder space aforesaid by passing therefrom through one of thedischarge slots 450 into one of the underlying discharge slots 53 to theinterior of the stationary sleeve 55 and thence back to the returnpassage 46 to the pumping engine.

If, however, the control lever 52 is moved in a direction which isclockwise in Fig. 4 and counter-clockwise in Fig. 5, the cylinder headabutments 430 and ii will be shifted correspondingly to the other sideof the inlet slots 56, whereupon the slot 450 in the reversing sleeve 60will register with inlet slot 56 and the slot 45l of the reversingsleeve will register with the outlet slot 64. Thus, 45i will become anoutlet and 450 will become an inlet, and the pressure on the vanes andthe rotor will be reversed, causing the rotor and the driven shaft i5 toturn in a reverse direction.

It is particularly to be noted that since the abutments 630 and Hill arecarried on the reversing sleeve which also carries the cam 350, thenecessary relationship between the parts which causes the pistons to belifted over the cylinder head abutments will be maintained in anyadjustment of the sleeve. It is further to be noted that in anintermediate sleeve position the abutments 430 may be centered over theinlet slot 56 in stationary sleeve 55 so that the pressure liquidsupplied through slots 56 will pass to both sides of the respectiveabutments and will immediately leave through the respective slots 450and HI and the underlying slots 63 and 64, thereby transmitting nomotion to the rotor of the motor engine. Obviously, therefore, thedevice herein disclosed provides for the operation of the motor enginein forward and reverse directions and for a neutral central position inwhich no motion of the motor occurs, the necessary controls beingincorporated directly in the interior of the motor engine while thecontrols incorporated in the interior of the pumping engine provide forautomatic control of the relative rate of operation of the. motor enginefrom the pump engine.

Those skilled in the art will appreciate that while, for purposes ofillustration, one of the engines has been called a pumping engine andthe other a motor engine, each is applicable for either function. If theshaft i5 is primarily driven, the engine at the right hand of Fig. 1will serve as a pump reversible as to output, while the engine at theleft of Fig. 1 will serve as a motor variable as to its relative speedrespecting the pump (assuming that the gearing connections are eitherremoved or are capable or delivering the power) The bottom of the caseserves as a slump in which any leaking oil is collected, serving tolubricate the moving parts. While the device may be filled in anydesired manner in the first instance, I have shown, as a convenient wayof introducing or withdrawing oil or other hydraulic fluid, a passage 55to the control rod portion 66 of the screw ll, such passage being closedat its outer end by a plug closure 51. v i

I claim:

1. In a hydraulic transmission having a pumping engine and a motorengine co-axially arranged, the combination with means providing acommunicating passage between said engines opening axially to a workingchamber of one of said engines and radially to a working chamber of theother, and means providing another communicating passage between saidengines opening radially to the working chambers of both of saidengines, of reversing means for reversing the communications of saidpassages with the engine to which they both open radially.

2. The combination defined in claim 1 together with means for varyingthe displacement of the other 01- said engines.

3. In a lwdraulic transmission having a first engine comprisingrelatively rotatable inner and outer members spaced to provide anannular cylinder, cylinder head means flxedto one of said members, vanesradially reciprocable in the other of said members, means for actuatingsaid vanes radially to clear the cylinder heads in the relative rotationof said members, and means providing a fluid communication passageopening axially from said cylinder space, a second engine 40 includingrelatively rotatable inner and outer members spaced to provide acylinder space with which said passage radially communicates, meanscarried by one of said second engine members providing cylinder heads insaid space and radially movable piston vanes carried by the other ofsaid second engine members, said second engine members having relativelymovable parts coacting for the radial movement of the piston vanes toclear said heads in the relative rotation of the second engine members,together with means providing a return passage from .the cylinder spaceof the second engine to the cylinder of the first engine.

4. The device of claim 3 in which the inner second engine member isoscillatory between selected positions for forward and reverse and isprovided with separate ports for affording communication from saidcommunication passages to v the second engine cylinder space at oppositesides of the respective cylinder heads accordingto the the oscillatorymember also shifting the relative point in the relative rotation of thesecond engine members at which the cylinder heads are located and atwhich the piston vanes are reciprocated to clear said cylinder heads.

5. In a hydraulic transmission, the combination with a casing comprisingcup-shaped sections, of a partition member between said sectionsprovided with a central annular flange, a sleeve supported in saidflange and provided with at least one slot extending axially of thesleeve through the partition, a tube axially reciprocable in the sleeveand provided with at least one port normally exposed beyond the sleeve,at least one cylinder head abutment member fixed to said tube anddisposed in the slot of the sleeve tor reciprocation in the slot whenthe tube is reciprocated respecting the sleeve, the abutment being ofless width than the slot whereby to leave a passage opening through thepartition, said port and passage constituting fluid inlet and exhaustmeans, a displacement annulus mounted on the tube for reciprocationtherewith and rotatable respecting the tube, an engine body rotatableabout the tube and having a portion spaced therefrom to afiord acylinder space within which. said abutment member is disposed andprovided with radial piston vane slots and means keyin said body withsaid annulus, the annulus being correspondingly slotted, piston vanesreciprocable in the slots into said space, means comprising a relativelyfixed part and a part relatively rotatable with said body having camsurfaces interacting in at least one direction for the reciprocation ofsaid vanes to clear the abutment of said tube in the course of relativerotation between said body and tube, and means for the axialreciprocation of said tube to advance said annulus between said body andtube in an axial direction, the slots of the annulus accommodating thereciprocation of the pistons, whereby to vary the liquid displacementcapacity of the cylinder space between the body and tube.

6. In a transmission having a pump as set forth in claim 5, thecombination with a control sleeve at the other side of the partitionoscillatably mounted externally of the sleeve first mentioned andprovided with ports selectively registerable with the slot of the sleevefirst mentioned according to the position of oscillation of the controlsleeve, said first sleeve also having ports with which the ports of thecontrol sleeve are alternatively registerable, of a cylinder headabutment mounted on the control sleeve between its aforesaid ports. anengine body mounted for rotation about the control sleeve in spacedrelation thereto to provide a cylinder space in which said lastmentioned abutment is disposed, said body having radial piston vaneslots, piston vanes in the slots of the last mentioned body, and cammeans reeiprocatively carried by the control sleeve and the body forinteraction in the course of relative rotation of the body respectingthe control sleeve, the cam means carried by the body being connectedwith the respective piston van-es for the reciprocation thereof in thecourse of such relative rotation to enable the piston vanes to clear thecylinder head abutment last mentioned, and the cam means carried by saidbody being movable therewith in the oscillatory adjustment of the bodywhereby to vary the location of the abutment when the relative positionsof the ports are varied and to effect a corresponding change of therelative point at which the piston vanes are reciprocated to clear suchan abutment, the ports of the first sleeve with which the ports of thecontrol sleeve alternatively register, as aforesaid, communicatingthrough the first sleeve with the interior of said tube and thence withthe cylinder space first mentioned.

'7. In a hydraulic transmission comprising a case and coaxial pump andmotor engines, one of which is variable only as to displacement and theother only as to direction of operation, the improvement which consistsin the combination of an axially movable tube disposed centrally in thecase and provided with one open end and with a plurality of radial portsintermediate its ends, said case being provided with means tor the axialadjustment of said tube. fixed cylinder head abutments carried by thetube adjacent the respective ports, a displacement annulus rotatablymounted on the tube and arranged for axial adjustment therewith, saidannulus being provided with axiallyextending slots, a rotor encirclinthe tube and spaced therefrom to provide a cylinder space in which saidabutments are disposed, said rotor comprising a body radially slotted inregistry with the slots of the displacement annulus, means keying thedisplacement annulus for rotation with said body, pistonvanesreciprocable in the slots of said body and adapted to enter the slots ofthe displacement annulus when the displacement annulus is moved withsaid tube into the cylinder space of the body, cam means operable in thecourse of relative rotation between the body and the tube for thereciprocation of the piston vanes to clear the respective abutments, asleeve extending axially of the tube ,to said cylinder space andproviding axial slots with corresponding sides of which the respectiveabutments of said tube are engaged and into which said abutments aremovable upon the reciprocation of said tube, means supporting theslotted sleeve, and ports extending radially through the slotted sleeveat either side of the slots first mentioned and communicating at theinterior of the sleeve with the open end of the tube, the engine whichcomprises reversing means including a control sleeve mounted foroscillatory adjustment upon the sleeve first mentioned and provided withports alternatively adjustable in the oscillation of the control sleevefor registra tion with the slot of the sleeve first mentioned, a port ofthe control sleeve out of registry with said slot being registered withone of the aforesaid ports of the sleeve first mentioned, fixed cylinderhead abutments carried by the control sleeve between its respectivepairs of ports, a rotor comprising a body rotatable about the controlsleeve and spaced therefrom to provide a cylinder space in which saidabutments last mentioned are disposed, sai body having radial pistonvane slots, piston vanes reciprocable in the respective slots, and cammeans carried in part by the control sleeve .and in part by said body,the part carried by the body having connections to the respective pistonvanes for the reciprocation thereof to clear the respective cylinderhead abutments last mentioned, a shaft connected with said body, andmeans for the oscillation of the control sleeve.

8. In a hydraulic transmission including a case and coaxial pump andmotor engines, one of which is variable only as to displacement and theother only as to direction of hydraulic flow therethrough, theimprovement which comprises the combination of a shaft projecting fromone end of the case and an adjusting rod projecting from the other, theengine which comprises displacement varying means being located in theother case end and including an annular boss about the rod, a camcarried by the boss, an engine rotor having a portion journaled withinthe boss, a displacement annulus rotatable and reciprocable within saidportion, a tube mounted for reciprocation and connected with said rod tobe controlled thereby, said annulus being rotatable upon the tube butconnected for reciprocation therewith and provided with axial slots, abody connected with the rotor and radially slotted in registry with theslots of the annulus, means keying the annulus for rotation with thebody, motion transmitting connections for said rotor,

piston vanes reciprocable in the slots of the body and the slots of theannulus when the annulus is moved axially within the body, cam followermeans connected with the rotor and coacting with said cam andoperatively connected for the reciprocation of the piston vanes in saidbody, said body being spaced from said tube to provide an annularcylinder into which said annulus is axially movable for displacement toreduce cylinder capacity, cylinder head abutments fixed to said tube andpositioned to be cleared by the piston vanes in their cam controlledreciprocation, said tube being ported'adjacent the respective abutmentsto afford communication between the interior of the tube and theaforesaid cylinder space, the case having a partition and the enginewhich comprises reversing means including, a a

sleeve supported by the partition and provided with a bearing for thetube and with axially extending slots in which the ends of therespective abutments are disposed and in which said abutments arelongitudinally movable in the reciprocation of the tube respecting saidsleeve, said slots having suilicient width to provide fluid passagesbeside the respective abutments opening into communication with thecylinder space aforesaid, said slots extending past the partition andthe said sleeve having beyond said partition pairs of ports, the portsof each pair being disposed at opposite sides of one of said slots andcommunicating through said sleeve with the open end of said tube, acontrol sleeve mounted for oscillatory adjustment on the outside of thesleeve first mentioned and provided with cylinder head abutments for thesecond engine and with ports in pairs at each side of the respectiveabutments so positioned that each of said ports may be registered withone of said slots for communication with the cylinder space of theengine first mentioned, the other slot of each pair being alternativelyregisterable with one of the ports of the sleeve first mentioned,whereby to communicate therethrough and to said tube with the cylinderspace of the engine first mentioned, a second engine rotor rotatableupon the adjustable control sleeve and including a body having radialslots and providing an annular cylinder space in which the controlsleeve abutments are located, vane pistons radially reciprocable in theseveral slots, a cam mounted on the control sleeve, cam follower meanscarried by the second engine rotor and operatively connected with therespective pistons to reciprocate said pistons to clear the controlsleeve abutments in the course of relative rotation between the secondengine rotor and the control sleeve, and an exterior handle in operativeconnection with said control sleeve for the oscillation thereof wherebyto reverse the flow through the cylinder space of said second engine,the second engine rotor being connected with the aforesaid shaft.

9. In a device of the character described, an engine which comprises afirst sleeve having at least one series of three ports for pressure andexhaust connections, the center port in the series comprising one ofsaid connections and the two external ports of the series comprising theotherof said connections, a control sleeve rotatable upon the sleevefirst mentioned and having at least one series of two ports in spacedrelation, each of said control sleeve ports being registerablealternatively with the central port of the first mentioned sleeve, theother control port, in each instance, registering with one of the endports of the series of ports of the control sleeve,

means for oscillating said control sleeve between positions in which itsrespective ports register with the central port of the control sleeveseries, a cylinder head abutment member carried by the control sleevebetween its ports. and an engine rotor including vane pistons and meansfor the reciprocation thereof rotatable about the control sleeve.

10. The structure defined in claim 9 in which the rotor is spaced fromthe control sleeve to provide an annular cylinder in which said abutmentis disposed and is provided with radial guideways opening from saidcylinder space, in which said vane pistons are reciprocable, saidcontrol sleeve having a cam comprising the means for reciprocationaforesaid and said rotor being provided with a series of cam followersconnected with the respective pistons and operatively engaging the camfor radially moving said pistons to clear said abutment, said cam andabutment being adjustable with the control sleeve in the movement of thesleeve between its aforesaid positions.

11. The structure defined in claim 9 in which the rotor is spaced fromthe control sleeve to provide an annular cylinder in which said abutmentis disposed and is provided with radial guideways opening from saidcylinder space, in which said vane pistons are reciprocable, saidcontrol sleeve having a cam comprising the means for reciprocationaforesaid and said rotor being provided with a series of cam followersconnected with the respective pistons and operatively engaging the camfor radially moving said pistons to clear said abutment, said cam andabutment being adjustable with the control sleeve in the movement of thesleeve between its aforesaid positions, the piston guide slots beingclosed at their outer ends and the several pistons being provided withradial passages for the relief of pressures between the pistons and theends of their respective slots.

12. The structure defined in claim 9 in which the rotor is spaced fromthe control sleeve to provide an annular cylinder in which said abutmentis disposed and is provided with radial guideways opening from saidcylinder space, in

which said vane pistons are reciprocable, said control sleeve having acam comprising the means for reciprocation aforesaid and said rotorbeing provided with a series of cam followers connected with therespective pistons and operatively engaging the cam for radially movingsaid pistons to clear said abutment, said cam and abutment beingadjustable with the control sleeve in the movement. of the sleevebetween its aforesaid positions, the pistons having central aperturesand the respective cam followers being mounted on rock shafts havingarms engaged in the piston apertures for the radially outwardreciprocation thereof, said rotor being provided with spring meansbiasing the pistons in opposition to the from the inner member, thecombination of a tube constituting the inner member of one of saidengines and provided with radial slotmeans affording communicationbetween the interior of the tube and the chamber of such engine and 6a,sae,a s

with a sleeve upon the tube havin: axiallyextending passage meansopening axially from the chamber space or the engine with which saidslot means communicates. and a. second sleeve constituting the innermember the other engine, such second sleeve being oscillatory upon thefirst sleeve and having slot means selectively registerabie with thepassage means of the first sleeve and with a slot means with which suchfirst sleeve is provided and which aflords communication with theinterior of such tube. where- 1 movement.

AAGE JENSEN.

